Field
The present invention relates to catheters for delivering a prosthesis and, particularly, to delivery catheters having an a traumatic distal tip assembly.
Background
Recently, minimally invasive approaches have been developed to facilitate catheter-based implantation of prostheses, for example, transcatheter aortic-valve prosthesis implantation. Typically, during transcatheter prosthesis implantations, a prosthesis is radially contracted onto a delivery catheter so that the prosthesis can be introduced into a body lumen, for example, into the femoral artery, the brachial artery, or the aorta, or into a body cavity, for example, a chamber of the heart (e.g., the ventricle). The contracted configuration of the prosthesis on the delivery catheter can be maintained by a retaining sleeve positioned over the prosthesis. Using the delivery catheter, the prosthesis can then be guided to the desired implantation site through the body lumen or body cavity. Once the prosthesis is advanced to a desired target site, the prosthesis can be deployed by removing the retaining sleeve and allowing the prosthesis to expand, for example, through balloon expansion or self-expansion.
A delivery catheter sometimes must be navigated through the tortuous anatomy of a body lumen or cavity. As the catheter articulates through the tortuous anatomy, the retaining sleeve can bend. The bending action of the retaining sleeve can cause the distal, leading edge of the retaining sleeve to flex outward (e.g., “fishmouth”) from an adjacent distal tip of the delivery catheter, exposing the distal edge. The exposed edge of the retaining sleeve can contact the wall of the body lumen or cavity, which can cause damage to the wall, especially in diseased body lumens. For example, during a trans-femoral delivery of a heart valve prosthesis, the delivery catheter must navigate around the aortic arch, which can cause the retaining sleeve to bend and can expose the retaining sleeve's distal, leading edge. The exposed leading edge of the retaining sleeve may damage the aortic wall if the edge contacts the wall.
Accordingly, there is a need for delivery catheters that have an atraumatic distal tip assembly that can reduce the risk of damage to the walls of the body lumen or cavity that may occur during delivery of a prosthesis to a desired target site.